Rocking blonde pigtails and a purple tutu, Zach has been living as a girl for more than a year, after he first refused to live as a boy when he turned three.

Little Zach was just three when he began refusing to live as a boy, instead choosing to wear pink dresses and ribbons in his long, blonde hair – because he has Gender Identity Disorder (GID).

And the primary school he attends in Essex has even changed the kids’ toilets to gender-neutral Unisex in support of Zach since his official diagnosis last year, aged four.

According to the Telegraph, Zach is one of the youngest in Britain ever to be diagnosed with GID – meaning he feels like he’s a girl trapped in a boy’s body.

His mother, Theresa Avery, 32, said Zach used to be a ‘normal’ little boy who loved Thomas the Tank Engine, but suddenly at the end of 2010, he decided he wanted to live as a girl.

He became obsessed with the girly kids’ TV character Dora the Explorer and started dressing in girls’ clothing.

Parents Theresa and Darren Avery, 41, became worried by Zach’s behavior and took him to the doctors.

After seeing a doctor, they found that he was officially diagnosed with Gender Identity Disorder (GID), making Zach one of the youngest affected children in the UK.

Theresa said:

“He just turned round to me one day when he was three and said: ‘Mummy, I’m a girl.’ I assumed he was just going through a phase and just left it at that.

But then it got serious and he would become upset if anyone referred to him as a boy. He used to cry and try to cut off his willy out of frustration.”

Concerned parents Theresa and Darren took him to a specialist at Tavistock and Patman Foundation Trust in London.

At first his parents thought he may be autistic, but after several months a child psychologist diagnosed Zach, affectionately called Zachy, with GID.

Theresa said, “They told us that although he had a male body, his brain was telling him he was a girl.”

As far as Zach’s school, Theresa said:

“They have changed the toilets for Key Stage 1 pupils into Unisex instead of male/female and they address him as a girl, which is what he wants.

When he gets a bit older, to Key Stage 2, then obviously the law changes and there will be more difficulties surrounding the bathroom issue, but we’ll cross that bridge when we come to it – it may be that Zach will use the staff toilets.”

A spokesperson at Tavistock Clinic in London said they were unable to comment on individual case, but only seven children under the age of 5 were diagnosed last year – making Zach one of the youngest.